After Effects should Alt drag to copy keyframes (multilayer too!)

Since ever, I would like to copy keyframes in a multilayer selection.

And once in a while I try to alt drag keyframes to duplicate 'm (since this is common gesture to make duplicates of anything in a lot of applications).

 

And now I think: maybe a combination of both is the ultimate way to make a dream come true!

There won't be any confusion of how the duplicates will be pasted, since all of those will keep their tracks.

 

Hope you can make this happen!